x86, realmode: Replace open-coded ljmpw with a macro

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We cannot code an ljmpw to the real-mode segment directly, because gas
refuses to assemble an ljmp with a symbolic segment.  Instead of
open-coding it everywhere, define a macro and use it for this case.

This is specifically an ljmpw from a 16-bit segment.  This is okay, as
one should never enter real mode from a 32-bit segment: if one do, the
CPU ends up in a bizarre (and useless) mode sometimes called "unreal
mode" where segments behave like real mode but the default address and
operand sizes is 32 bits.

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Link: http://lkml.kernel.org/r/1336501366-28617-15-git-send-email-jarkko.sakkinen@intel.com

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This commit is contained in:

H. Peter Anvin 2012-05-08 21:22:37 +03:00

parent 968ff9ee56

commit e5684ec438

5 changed files with 25 additions and 16 deletions

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16

arch/x86/realmode/rm/realmode.h

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6

arch/x86/realmode/rm/reboot_32.S

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5

arch/x86/realmode/rm/trampoline_32.S

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5

arch/x86/realmode/rm/trampoline_64.S

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9

arch/x86/realmode/rm/wakeup/wakeup_asm.S

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